I just checked: I did a What's New "Documents" type search , and quite a few PDF's showed up.

If you try and don't get any, check the options under Sharing, and also under filters.

There is a box in the Sharing options that lists all file types you can choose to share. Check to see if the .pdf extension is listed in yours--maybe it was removed somehow.

Under Filters, certain file types can be excluded, so that's the other place where pdf's might be blocked.